Thread: Breaking Lugs

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1968 C-10 1/2 ton Chevy pick up truck. 6 lugs. 7/16". This truck has big wide Rally wheels on it. Had the tuck about 3 years. It,s always brakeing the front lug nuts. All on them. I guess the big wide wheels and tires just put to much pressure on them. Not the stock wheels ofcourse. What I,m going to do. Is put some 1/2" lugs on the Wheel thing.( don,t know what it,s called.) What I would like to know is. What size should drilled the holes out to put the 1/2" Lugs in?

Breaking lug studs indicates that something serious is going on. Are the wheels made for the Chevy 7/16" studs? Do not use 1/2" hole wheels on a vehicle with 7/16" studs. Is someone overtightening the lug nuts ..... OR severely undertightening them? Find the specification for your truck and use that torque. Retorque the lug nuts after a day. Check them periodically to see if they are loosening.

How many times has this happened? Did all of the studs break the same time? If each stud location has broken only once, could someone have overtightened the studs at some time in the truck's life?

Putting larger diameter studs is tough if the wheels are drilled for 7/16" dia studs. Also, there are quite a few stud models....each has a knurl diameter that is pressed into the hub. The diameter of the knurl determines the diameter of the hole....the knurl dia is larger than the hub hole diameter so there is some metal deformation when the stud is pressed in. You have to match the knurl length to the thickness of the hub, etc. I dont think that going to 1/2" studs is the answer...it is a band aid and does not fix the root problem.

mike in tucson

Mike, Thank you very much for your reply. The history of the truck is this. I bought the truck about 3 years ago. The big rally wheels and tires were on the truck. Not long after I had the truck. One of the front lugs broke. So I replace it with a new lug. About a week later. Another lug broke on the other front wheel. I replace it. Every so often after that one or two lugs would brake. After a while I had replaced every lug on both front wheels. 12 lugs in all. And I would say per haps over the last two years I,ve replaced about 25 lugs. They would at first only brake one or two at a time. But now they all will brake. The truck has the old drum type brake drums. I inten to replace them with a calbier type wheel. So the 1/2 lugs are intened to be a temperary fix. Do they make lugs that would not brake? The ones I have been buying are stock lugs from Auto Zone. Perhaps that is why they are braking. LOL.

And by the way. The holes on the wheels do look like thier made for a 1/2" lug.

If the holes are too big the nuts will bottom out against the drum and not hold the wheel tightly. The result is the wheel working and breaking the studs.

John,

The lug studs sold at AutoZone, PEP Boys, etc are usually Dorman brand, the standard of the industry. Lug stud quality is not the problem. Are you buying the correct stud? Just because the thread is the same DOES NOT mean that the stud is correct. The diameter and length of the knurl is also very important.

Did you measure the hole in the wheels....see REM's message above.